Glutaric acidemia type 1 | |
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Glutaric acid | |
Classification and external resources | |
Specialty | endocrinology |
ICD-10 | E72.3 |
OMIM | 231670 |
DiseasesDB | 29830 |
Glutaric acidemia type 1 (or "Glutaric Aciduria", "GA1", or "GAT1") is an inherited disorder in which the body is unable to break down completely the amino acids lysine, hydroxylysine and tryptophan. Excessive levels of their intermediate breakdown products (glutaric acid, glutaryl-CoA, 3-hydroxyglutaric acid, glutaconic acid) can accumulate and cause damage to the brain (and also other organs), but particularly the basal ganglia, which are regions that help regulate movement. GA1 causes secondary carnitine deficiency, as glutaric acid, like other organic acids, is detoxified by carnitine. Mental retardation may also occur.
The severity of glutaric acidemia type 1 varies widely; some individuals are only mildly affected, while others have severe problems. GA1 can be defined as two clinical entities: GA1 before the encephalopathic crisis and GA1 after the encephalopathic crisis.
Babies with glutaric acidemia type 1 often are born with unusually large heads (macrocephaly). Macrocephaly is amongst the earliest signs of GA1. It is thus important to investigate all cases of macrocephaly of unknown origins for GCDH deficiency, given the importance of the early diagnosis of GA1. Macrocephaly is a "pivotal clinical sign" of many neurological diseases. Physicians and parents should be aware of the benefits of investigating for an underlying neurological disorder, particularly a neurometabolic one, in children with head circumferences in the highest percentiles.
Affected individuals may have difficulty moving and may experience spasms, jerking, rigidity or decreased muscle tone and muscle weakness (which may be the result of secondary carnitine deficiency). Glutaric aciduria type 1, in many cases, can be defined as a cerebral palsy of genetic origins.
A common way to manage striatal necrosis is to provide special seating. These special wheelchairs are designed to limit abnormal movements. However, spasticity can be worsened by constraint.